1. Field of the Invention
The present invention relates in general to a hand-held vibratory massager, and more particularly to a vibratory massager with an arcuately extensible arm interconnecting a grip and a self-contained vibratory applicator.
2. Description of the Prior Art
As disclosed in Japanese Early Patent Publication (Kokai) No. 54-109290, there has been already proposed a hand-held vibratory massager with an extensible straight arm interconnecting a hand grip and a self-contained vibration applicator. Such extensible prior art massager is advantageous in locating the applicator over a wide area of a user's body, including thigh, knee, leg, foot, and back by suitably extending the straight arm. However, since the applicator is required to be continuously pressed against a selected portion of the body, this prior art vibrator with the straight extensible arm is only successful in providing a massaging action to the front of the body where both hands of the user are available for holding the vibrator and at the same time for applying sufficient force to continuously press the applicator to the selected portion. Such continuous sufficient pressing force is normally obtained by holding the end of the hand grip by one hand and supporting the hand grip at a portion spaced from the end by the other hand, and then by pivoting the grip end by the one hand about the spaced portion supported by the other hand in a lever-like system. In this sense, the prior art massager even with its arm extended is practically difficult to use to give a massaging action to a portion, such as the back of the user, where only one hand of the user is available and therefore both hands are not available to effect the above lever-like system for producing sufficient pressing force at the applicator. In this condition, the user is required instead to bend or twist the wrist to produce a torque about the end of the hand grip in order to obtain a sufficient pressing force at the applicator. That is, as shown in FIG. 21, when massaging the back or waist, the user has no way but to hold the massager by one hand and is therefore required to twist the hand grip for producing a torque required to place the applicator to the desired portion at a sufficient pressing force. Assuming that the user gives a constant torque T, and when the massager is extended from a normal position of placing the applicator z a distance D1 away from the hand holding the grip 1 to an extended position of placing the applicator 2 an increased distance D2 away from the same, the applicator 2 is given at its normal and extended positions respectively pressing forces W.sub.1 (=T/D.sub.1) and W.sub.2 (=T/D.sub.2). As apparent from the above, pressing force W.sub.2 at the extended position is eventually less than W.sub.1 as D.sub.2 &gt;D.sub.1. This means that as the vibrator extends, the resulting pressing force will be reduced, which invalidates the extensible feature of the vibrator. In other words, in order to keep providing sufficient pressing force at the applicator in its extended position, the user has to increase the torque with attendant accumulation of fatigue of the wrist, making it difficult to continue the massaging.